The most varied types of conveyor belts are utilised today for the transport of foodstuffs. In addition to many other areas of application, these are also used in hygiene sensitive zones. Used in this connection are, for example, plastic layered textile belts, monolithic plastic belts or also modular plastic belts, which consist of a plurality of modules linked together. Since the foodstuffs come directly in contact with the conveyor belts, regular cleaning of the conveyor belts and of other parts of the conveying system is necessary, in order to avoid a contamination of the foodstuffs with old and possibly partly already decomposed remnants of foodstuffs and micro-organisms, like, for example, microbes, bacteria, fungi, yeasts, viruses etc. A good ability to be cleaned is therefore an important requirement for conveyor belts, in particular foodstuff conveyor belts. The conveyor belts, as well as other openly accessible parts of the conveyor system, should be able to be cleaned as well and as quickly as possible with low as possible costs.
In the case of modular belts, the individual modules made from hard plastic as such are normally able to be cleaned well, but in the area of linkage, typically gaps are present, in which foodstuff remnants penetrate and can get caught in, which are then difficult to remove.
With non-modular, continuous conveyor belts no links to connect the belt modules are present, so that no areas of linkage must be cleaned. These continuous conveyor belts are relatively thin and flexibly constructed, such that they can be bent and moved around deflection and driving rollers and toothed wheels respectively.
Such a flexible conveyor belt is known for example from WO 03/076311 A1, that has a smooth conveyor side, as well as a driving side, on which driving ridges are arranged which are equally spaced apart in the direction of travel of the conveyor belt and run transverse to the direction of travel of the conveyor belt. The conveyor belt is guided around driving rollers and is driven via the driving ridges by the driving rollers. In doing so the problem can arise that the conveyor belt displaces laterally on the driving rollers and disconnects from these.
This problem is usually solved by laterally arranging guiding elements next to the conveyor belt, which prevent a lateral displacement of the conveyor belt. Such guiding elements are, for example, guide rails on the conveyor device or also surrounding disks on the driving rollers, which rotate with them, such that the conveyor belt is not slowed down through contact with the guiding elements.
However such guiding elements next to the conveyor belt have the disadvantage that they are additional components, which increase the width of the conveyor device and which must also additionally be cleaned. Furthermore, they can potentially impede the cleaning of the driving rollers.
From U.S. Pat. No. 2,770,977 A it is known to provide driving ridges of a flat belt, which run transverse to the direction of travel of the belt, with longitudinal ridges for longitudinally guiding the belt on teeth of a driving toothed wheel. These longitudinal ridges have the disadvantage that they create corners and angles that are only difficult to clean.